Two stainless steel M6 screws per ring and a flat base for best contact with the dovetail bar eliminate twisting or differential flex, which improves guiding accuracy. All-metal thumbscrews to eliminate flex.

Rings have a flat base with 2x M6 holes to attach to a 200mm dovetail bar. A Starwave 200mm dovetail bar (product code SW-VBAR-200) is included with standard 44.5mm maximum width (Starwave/Synta/Vixen-format).

Rings can be positioned at 60, 120 or 180mm separation along the dovetail bar depending on the length of the guide scope.

Special pads on the ends of the thumbscrews reduce the chance of chipped paint and scratches, without allowing movement.

There are many cheap guidescope rings on the market, however they usually have "differential flex" problems, This is where the guide scope moves (even very slightly) relative to the main imaging telescope, causing the wrong corrections to be sent to the mount. These problems are caused by:

Nylon or plastic thumbscrews used for alignment and holding the optical tube

Guidescope rings without a flat surface machined into the base which rock from side to side

Guidescope rings which attach to the dovetail bar with only one screw, allowing them to swivel

Cheap modified finder scopes which rely on a rubber O-ring around the front to keep them aligned in their bracket

Starwave guide scope rings solve all of these problems, and as long as your guide scope itself doesn't have flex in the focuser, they offer the best performance possible for the price.